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Certain Physico‐Chemical Properties of the Pinchen Clay and the Function of Its Free Iron Oxide and Organic Matter
Author(s) -
KunHuang Houng,
Tsentuo Chen
Publication year - 1959
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1959.03615995002300040013x
Subject(s) - adsorption , chemistry , moisture , clay minerals , iron oxide , cation exchange capacity , oxide , organic matter , soil water , humic acid , water content , porosity , surface tension , inorganic chemistry , mineralogy , soil science , geology , organic chemistry , thermodynamics , fertilizer , geotechnical engineering , physics
Tension‐moisture content relationships of the deferrated soils and control soil indicated that available moisture was reduced from 10.3% to 7.3% as the result of deferration. From the study of vapor adsorption isotherms, the constants of the BET equation were derived. Deferration increased the standard free energy of adsorption of water on the bare surface, ΔF° 1 , and decreased the specific surface, S, while oxidation decreased both ΔF° 1 and S. The deferrated clay was dispersed easier by humic acid, showed less buffering effect against Ba(OH) 2 , and a decrease in exchange capacity; whereas oxidized clay gave a stronger buffering effect against NaOH. The energy of replacement of Ca by K showed no difference between variously treated clays, indicating binding force of cations at exchange sites was little affected by presence of organic matter or iron oxide. It was concluded that the principal clay minerals and free iron oxide forming fine porous coating might be regarded as the dominant factors affecting moisture and surface characteristics of the Pinchen clay.